NEW YORK — A man swinging a samurai sword at an Apple store terrified shoppers on Friday.

The man walked into the Manhattan store and began waving the sword, authorities said. A video posted online showed him swinging the sword as he walked down a staircase.

Lawyer Nancy Birnbaum, who lives nearby, told the New York Post she was browsing at the store when she spotted the man on the staircase.

“I thought he was doing some sort of performance art, but then he pulls out this sword with a huge 2-foot-long blade, and it was dead obvious that it was a real sword,” she said. “I’ve never been so terrified in my entire life.”

The man appeared to be emotionally disturbed, police said. He was taken into custody at the scene, and his name was not immediately released. No injuries were reported.

A spokesman for Apple, which is based in Cupertino, confirmed the incident but declined to comment further.